Crystal Structure and Physical Properties of the New Chalcogenides Ba<sub>3</sub>Cu<sub>17–<i>x</i></sub>(S,Te)<sub>11</sub> and Ba<sub>3</sub>Cu<sub>17–<i>x</i></sub>(S,Te)<sub>11.5</sub> with Two Different Cu Clusters
Bibliographic record
Abstract
The sulfide-tellurides Ba<sub>3</sub>Cu<sub>17–<i>x</i></sub>(S,Te)<sub>11</sub> and Ba<sub>3</sub>Cu<sub>17–<i>x</i></sub>(S,Te)<sub>11.5</sub> were synthesized from the elements in stoichiometric ratios heated to 1073 K, followed by slow cooling to 873 K over 100 h. Ba<sub>3</sub>Cu<sub>17–<i>x</i></sub>(S,Te)<sub>11</sub> is isostructural to Ba<sub>3</sub>Cu<sub>17–<i>x</i></sub>(Se,Te)<sub>11</sub> when [S] > [Te], space group <i>R</i>3̅<i>m</i>, with lattice dimensions of <i>a</i> = 12.009(1) Å, <i>c</i> = 27.764(2) Å, <i>V</i> = 3467.6(5) Å<sup>3</sup>, for Ba<sub>3</sub>Cu<sub>15.7(4)</sub>S<sub>7.051(5)</sub>Te<sub>3.949</sub> (<i>Z</i> = 6). The structure is composed of Cu atoms forming paired hexagonal antiprisms, capped on the two outer hexagonal faces, where each Cu atom is tetrahedrally coordinated by four <i>Q</i> (= S, Te) atoms. The new variant is formed when [Te] > [S]; then Ba<sub>3</sub>Cu<sub>17–<i>x</i></sub>(S,Te)<sub>11.5</sub> adopts space group <i>Fm</i>3̅<i>m</i> with <i>a</i> = 17.2095(8) Å, <i>V</i> = 5096.9(4) Å<sup>3</sup>, for Ba<sub>3</sub>Cu<sub>15.6(2)</sub>S<sub>5.33(4)</sub>Te<sub>6.17</sub> (<i>Z</i> = 8). This structure consists of eight Te-centered Cu<sub>16</sub> icosioctahedra per cell interconnected by cubic Cu<sub>8</sub> units centered by <i>Q</i> atoms. Electronic structure calculations and property measurements illustrate that these compounds behave as extrinsic <i>p</i>-type semiconductorstoward metallic behavior for the latter compound. With standard oxidation states Ba<sup>2+</sup>, Cu<sup>+</sup>, and <i>Q</i><sup>2–</sup>, the electron precise formulas are Ba<sub>3</sub>Cu<sub>16</sub><i>Q</i><sub>11</sub> and Ba<sub>3</sub>Cu<sub>17</sub><i>Q</i><sub>11.5</sub>.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.008 | 0.008 |
| Meta-epidemiology (narrow) | 0.024 | 0.020 |
| Meta-epidemiology (broad) | 0.022 | 0.010 |
| Bibliometrics | 0.007 | 0.012 |
| Science and technology studies | 0.013 | 0.012 |
| Scholarly communication | 0.011 | 0.013 |
| Open science | 0.022 | 0.020 |
| Research integrity | 0.011 | 0.011 |
| Insufficient payload (model declined to judge) | 0.013 | 0.004 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; both teacher heads agree on what is shown here.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".